Hello
here's a diatom pic whose stereopairs kept me exploring it for longer than any other before. I guess it's a Hyalodiscus spec, couldn't find any closer match to identify it further. It's from Oamaru as well.
EPI darkfield, 50x Neo Splan.
Diameter pretty much exactly 100µm, distance of the pores on the outer ring ~360nm.

Crosseyed total:

Crosseyed closer - interestig to see the different layers of the pores

And a really close one that only makes sense in 3D - I think it is amazing that you can actually see the pores as little "tubes" on the edge. Remember they're less than half a micron apart. You cannot really tell this from the "mono" image, but in stereo, there's no doubt.